Determination of vanadium in sea water by x-ray fluorescent spectrometry

For the X-ray fluorescent determination of vanadium in water, the preconcentration with sodium diethyldithiocarbamate (DDTC) and coprecipitant was investigated. Trace vanadium-DDTC complex did not precipitate completely, while it coprecipitated quantitatively with chromium (VI), iron (III), iron (II) or cobalt (II) which formed stable DDTC-complexes in the pH range from 3 to 5. 0.5 mg of coprecipitant and 20 ml of 10 w/v% sodium acetate buffer were added to 500 ml of a sample solution. The solution was adjusted to pH 4.0, and then added to 3 ml of 2 w/v% DDTC solution. The coprecipitant including vanadium was then collected to undergo an X-ray fluorescent analysis. A microgram per liter level of vanadium in sea water was determined by calibration curve method. (author)